Lunyu IV. 18. (84)

How a son may remonstrate with his parents on their faults.
The Master said, "In serving his parents, a son may remonstrate with them, but gently; when he sees that they do not incline to follow his advice, he shows an increased degree of reverence, but does not abandon his purpose; and should they punish him, he does not allow himself to murmur."

Legge IV.18.

The Master said, 'In serving your father and mother you ought to dissuade them from doing wrong in the gentlest way. If you see your advice being ignored, you should not become disobedient but should remain reverent. You should not complain even if in so doing you wear yourself out.'